A pathway to synthesizing single-crystal Fe and FeCr films

B. Derby; J. Cooper; T. Lach; E. Martinez; H. Kim; J. K. Baldwin; D. Kaoumi; D. J. Edwards; D. K. Schreiber; B. P. Uberuaga; N. Li

doi:10.1016/j.surfcoat.2020.126346

A pathway to synthesizing single-crystal Fe and FeCr films

B. Derby, J. Cooper, T. Lach, E. Martinez, H. Kim, J. K. Baldwin, D. Kaoumi, D. J. Edwards, D. K. Schreiber, B. P. Uberuaga, N. Li

Research output: Contribution to journal › Article › peer-review

7 Scopus citations

Abstract

Nuclear reactor environments provide a unique scientific and engineering challenge wherein materials must tolerate prolonged exposure to concurrent irradiation, elevated temperatures, and corrosive media. However, uncontrolled variability in material composition and structure often prohibits truly single-variable experiments that can reveal basic aspects of environmental damage. Magnetron sputtering is used here to provide a more controlled model system for these fundamental studies, yielding reproducible single-crystal Fe and FeCr thin films containing 8 and 18 at.% Cr. Electron microscopy is used to determine the systematic correlations between growth conditions and the resulting film microstructure and surface morphology. It is found that the substrate temperature and applied radio frequency (RF) bias can be tuned to obtain consistent homogeneous and single crystal films with a minimal amount of Ar impurities from the RF bias process. Epitaxial, single-crystal Fe films are obtained on MgO substrates at 500 °C with 10 Watt (W) RF bias deposition. However, when Cr is alloyed with Fe, higher substrate temperatures (600 °C) and applied RF biases (15 W) are required to achieve a similar epitaxial single-crystal FeCr film. Accelerated molecular dynamics simulations reveal that Cr impedes surface transport, explaining the need for higher temperature and bias during the growth of the Cr-bearing films.

Original language	English
Article number	126346
Journal	Surface and Coatings Technology
Volume	403
DOIs	https://doi.org/10.1016/j.surfcoat.2020.126346
State	Published - Dec 15 2020
Externally published	Yes

Funding

This work was supported by FUTURE (Fundamental Understanding of Transport Under Reactor Extremes), an Energy Frontier Research Center funded by the U.S. Department of Energy (DOE), Office of Science, Basic Energy Sciences. E.M. acknowledges support by the U.S. DOE , Office of Science, Office of Fusion Energy Sciences, and Office of Advanced Scientific Computing Research through the Scientific Discovery through Advanced Computing (SciDAC) project on Plasma-Surface Interactions under award number DE-SC0008875 . Part of this work was performed at the Analytical Instrumentation Facility (AIF) at North Carolina State University, which is supported by the State of North Carolina and the National Science Foundation (award number ECCS-1542015 ). This work was performed, in part, at the Center for Integrated Nanotechnologies, an Office of Science User Facility operated for the U.S. DOE Office of Science. Los Alamos National Laboratory, an affirmative action equal opportunity employer, is managed by Triad National Security, LLC for the U.S. DOE 's NNSA, under contract 89233218CNA000001 . Pacific Northwest National Laboratory is a multi-program national laboratory operated by Battelle for the U.S. DOE under contract DE-AC05-76RL01830 .

Funders	Funder number
Fundamental Understanding of Transport Under Reactor Extremes
National Science Foundation	ECCS-1542015
U.S. Department of Energy
Office of Science
Basic Energy Sciences
Advanced Scientific Computing Research	DE-SC0008875
Fusion Energy Sciences
North Carolina State University
Los Alamos National Laboratory	89233218CNA000001, DE-AC05-76RL01830

Keywords

Film growth
Magnetron sputtering
Single crystal Fe and FeCr films
TEM

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title = "A pathway to synthesizing single-crystal Fe and FeCr films",

abstract = "Nuclear reactor environments provide a unique scientific and engineering challenge wherein materials must tolerate prolonged exposure to concurrent irradiation, elevated temperatures, and corrosive media. However, uncontrolled variability in material composition and structure often prohibits truly single-variable experiments that can reveal basic aspects of environmental damage. Magnetron sputtering is used here to provide a more controlled model system for these fundamental studies, yielding reproducible single-crystal Fe and FeCr thin films containing 8 and 18 at.% Cr. Electron microscopy is used to determine the systematic correlations between growth conditions and the resulting film microstructure and surface morphology. It is found that the substrate temperature and applied radio frequency (RF) bias can be tuned to obtain consistent homogeneous and single crystal films with a minimal amount of Ar impurities from the RF bias process. Epitaxial, single-crystal Fe films are obtained on MgO substrates at 500 °C with 10 Watt (W) RF bias deposition. However, when Cr is alloyed with Fe, higher substrate temperatures (600 °C) and applied RF biases (15 W) are required to achieve a similar epitaxial single-crystal FeCr film. Accelerated molecular dynamics simulations reveal that Cr impedes surface transport, explaining the need for higher temperature and bias during the growth of the Cr-bearing films.",

keywords = "Film growth, Magnetron sputtering, Single crystal Fe and FeCr films, TEM",

author = "B. Derby and J. Cooper and T. Lach and E. Martinez and H. Kim and Baldwin, {J. K.} and D. Kaoumi and Edwards, {D. J.} and Schreiber, {D. K.} and Uberuaga, {B. P.} and N. Li",

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AU - Derby, B.

AU - Cooper, J.

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AU - Martinez, E.

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AU - Baldwin, J. K.

AU - Kaoumi, D.

AU - Edwards, D. J.

AU - Schreiber, D. K.

AU - Uberuaga, B. P.

AU - Li, N.

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N2 - Nuclear reactor environments provide a unique scientific and engineering challenge wherein materials must tolerate prolonged exposure to concurrent irradiation, elevated temperatures, and corrosive media. However, uncontrolled variability in material composition and structure often prohibits truly single-variable experiments that can reveal basic aspects of environmental damage. Magnetron sputtering is used here to provide a more controlled model system for these fundamental studies, yielding reproducible single-crystal Fe and FeCr thin films containing 8 and 18 at.% Cr. Electron microscopy is used to determine the systematic correlations between growth conditions and the resulting film microstructure and surface morphology. It is found that the substrate temperature and applied radio frequency (RF) bias can be tuned to obtain consistent homogeneous and single crystal films with a minimal amount of Ar impurities from the RF bias process. Epitaxial, single-crystal Fe films are obtained on MgO substrates at 500 °C with 10 Watt (W) RF bias deposition. However, when Cr is alloyed with Fe, higher substrate temperatures (600 °C) and applied RF biases (15 W) are required to achieve a similar epitaxial single-crystal FeCr film. Accelerated molecular dynamics simulations reveal that Cr impedes surface transport, explaining the need for higher temperature and bias during the growth of the Cr-bearing films.

AB - Nuclear reactor environments provide a unique scientific and engineering challenge wherein materials must tolerate prolonged exposure to concurrent irradiation, elevated temperatures, and corrosive media. However, uncontrolled variability in material composition and structure often prohibits truly single-variable experiments that can reveal basic aspects of environmental damage. Magnetron sputtering is used here to provide a more controlled model system for these fundamental studies, yielding reproducible single-crystal Fe and FeCr thin films containing 8 and 18 at.% Cr. Electron microscopy is used to determine the systematic correlations between growth conditions and the resulting film microstructure and surface morphology. It is found that the substrate temperature and applied radio frequency (RF) bias can be tuned to obtain consistent homogeneous and single crystal films with a minimal amount of Ar impurities from the RF bias process. Epitaxial, single-crystal Fe films are obtained on MgO substrates at 500 °C with 10 Watt (W) RF bias deposition. However, when Cr is alloyed with Fe, higher substrate temperatures (600 °C) and applied RF biases (15 W) are required to achieve a similar epitaxial single-crystal FeCr film. Accelerated molecular dynamics simulations reveal that Cr impedes surface transport, explaining the need for higher temperature and bias during the growth of the Cr-bearing films.

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A pathway to synthesizing single-crystal Fe and FeCr films

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Keywords

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